Figured I'd have a go of this since I found two-pronged driver to get the case open.
I found a leak mark under the large electrolytic C2. Replaced with a a longer life 22uF 400V nichicon.
Replaced the other cap in that board.
Headers from the LED / batteries under charge +ve board were corroded and there is corresponding pad damage on the main board.
Waiting for copper sheet in the post to cut new pads
Ordered up 1 row and two row bent headers and replaced.
I've got caps to recap throughout but i'll see how things go.
Channel 2 is on all the time
Channel 5 and 6 do nothing.